adding SYNC to a non-equipped car

Has anyone added Sync to a non-SYNC equipped car? I'm trying to find out how involved it would be. I've got a 2008 SE Focus. I've seen a 6-disc changer with Sync and the steering wheel controls and need to know if it would be a plug and play; or is it more involved with a separate computer module. Any idea if if affects the security system? Thanks.

More involved, at least 2 modules needed. Not to mention new steering wheel buttons, a new rearview mirror, the wires for the mic in the mirror, the modules have a few different bus systems to communicate with eachother.